The Human Organism. Nutri1on Lecture 2 The Energy Value of Nutrients

Transcription

1 The Human Organism Nutri1on Lecture 2 The Energy Value of Nutrients

2 Nutri1on Nutrient is a substance found in food that is used by the body to meet important needs 6 types of nutrients: Proteins Carbohydrates Fats Minerals Vitamins Water

3 Nutrient Roles Each type of nutrient plays an important role in the human organism See page Table 6.3 Amount of energy needed per person depends on factors such as age, sex, weight, level of PA, and overall health Adolescents need??? Pg. 161 fig.6.2

4 The Energy Value of Nutrients: How much energy is a nutrient worth? Cells obtain most of their energy from carbohydrates and fats. Remember your en1re body is made up of cells! Protein can supply the body with energy if in need (if you run out of carbohydrates and fats)

5 Cellular respira1on Cellular respira1on allows the release of stored energy from a nutrient molecule Remember: Energy is not created or destroyed So the energy moves from the piece of food into your body. Glucose + Oxygen Energy + Water + Carbon dioxide

6 Energy value of nutrients Energy value of nutrients: the amount of energy the nutrient will give the body. It is measured in kilojoules (kj) Most of the energy comes from fats 1 g of fat = 37 kj of energy 1 g of carbohydrate = 17 kj of energy 1 g of protein = 17 kj of energy Vitamins, minerals and water supply NO ENERGY! They help balance your body (homeostasis)

7 Energy needs Each of us needs a different amount of energy each day This is based on our age, sex, body type, hereditary factors, physical ac1vity level, etc.

8 Reminder On average teens between the ages of need Girls: Cal ( kj) and Boys: Cal ( kj) 1 Calorie = kj

9 Energy Output Pg 164 fig. 6.4 Energy output helps balance energy input in order to have a healthy body Energy value average. See table on pg 164 fig. 6.5 What is fiber and how does it aid in diges1on? - Hint Pg 165

10 Basal metabolism Basal metabolism = the energy we need to maintain vital func1ons (like your heartbeat) It uses up the most amount of energy each day

11 Other energy needs Physical ac1vi1es require a certain amount of energy too: Physical ac*vity Energy expenditure per hour (kj) Walking 515 Jogging 1130 Dancing 1230 Basketball 1435 Soccer 2050 A person who does a lot of physical ac1vity will need more energy (from food) than a person who is sedentary Diges1on needs energy too: about 10% of your energy

12 Mee1ng energy requirements To make sure you have enough energy you need to eat a certain amount of carbohydrates, fats, and proteins. Nutri*onal requirements In kilojoules Carbohydrates Fats Proteins 55% of kj ingested 30% of kj ingested 15% of kj ingested

13 Gaining and loosing energy Your weight is a reflec1on of the amount of energy you take in and the amount of energy you use each day If you want to maintain your weight: E intake = E used If you want to lose weight: E intake < E used If you want to gain weight: E intake > E used

14 Pure Substances Pure substance: substance containing only one type of par1cle Ex: dis1lled water, sugar, iron, copper, diamonds Pure substances can be classified as either compounds or elements What is an ex. Of an element? A compound?

15 Elements and Compounds Elements is a pure substance that contains only one type of atom It is impossible to separate using chemical separa1on techniques Compound is Pure substance that contains at least 2 types of atoms that are chemically combined Using chemical separa1on techniques it can separate into its cons1tuents

16 Homogeneous and Heterogeneous mixtures Mixture: consists of at least 2 different substances. Contains at least 2 types of par1cles. 2 kinds of mixtures Heterogeneous Homogeneous Heterogeneous mixture is made up of at least 2 substances that can be dis1nguished with the naked eye

17 Mixtures cont. Homogeneous mixture is made up of at least 2 substances that cannot be dis1nguished with the naked eye Colloid: a homogeneous mixture where at least 2 different substances can be dis1nguished under a magnifying glass Ex: blood, homogenized milk Pg. 11 Solu1on: a homogeneous mixture where it s impossible to dis1nguish cons1tuent parts (even under a magnifying glass) Pg 10 Fig Iden1fy each of the pictures as either type of mixture